Method and apparatus for providing a conductive, amorphous non-stick coating

ABSTRACT

A conductive, non-stick coating is provided using a ceramic material which is conductive, flexible and provides a surface which exhibits the property of lubricity. A room or near room temperature manufacturing process produces a coating of titanium nitride on a substrate, where the coating is amorphous if the substrate is a solid material including plastics, composites, metals, magnets, and ceramics, enabling the substrate to bend without damaging the coating. The coating can also be applied as a conformal coating on a variety of substrate shapes, depending upon the application. The coating is bio-compatible and can be applied to a variety of medical devices.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention pertains to a method for providing a conductive,non-stick coating at or near room-temperature to many materials whichcan benefit therefrom. More specifically, the present invention pertainsto a method and apparatus for applying the conductive, non-stick coatingto different materials, as well as presenting various embodiments whichcan take advantage of the coating's properties includingbio-compatibility, flexibility, radio-opacity, diffusion resistance,wear and corrosion resistance, hardness, ability to be hydrophobic orhydrophilic, adherence to multiple materials, sterilizability, andchemical inertness and stability.

[0003] 2. State of the Art

[0004] The present invention was originally developed as a result toimprove electrosurgical instruments used in cauterization and othermedical procedures, as well as to provide a bio-compatible coating forlong-term implantable blood pumps. For example, prior U.S. patents havebeen issued for various electrosurgical blades which apply a non-stickcoating to a cutting edge thereof. These blades typically suffered fromsmall openings in the non-stick coating which were sometimesintentionally allowed to form in order to ensure electrical conductivityalong the cutting edge. Exposing the metallic surface of the bladedisadvantageously resulted in charred tissue sticking to these areas.The result was that the blade quickly became non-conductive andconsequently unusable.

[0005] In an attempt to improve the blade, Blanch was granted U.S. Pat.No. 4,785,807 (the '807 patent) for teaching an electrosurgical bladewhich has a cutting edge of the blade which is abraded or etched, and acoat of a non-stick fluorinated hydrocarbon material which is appliedover the etched cutting edge. A coating of non-stick material covers thesurface area of the cutting blade and is intended to eliminate or reducethe clinging of charred tissue to the blade. By eliminating the smallopenings in the non-stick coating of previous blades, the blade betterinhibited the build up of charred tissue. However, one drawback in theprinciple of the '807 patent is that the non-stick coating is notparticularly durable, and will wear off after repeated usage. This istrue partly because the non-stick and non-conductive coating has theproperties of an insulator and had to be kept thin in order to enablethe radio-frequency energy to pass through the non-stick coating to thetissue to cut and/or cauterize.

[0006] Another drawback of the blade described in the '807 patent isthat the non-stick coating is not flexible. This inability to bend theelectrosurgical blade seriously limits the options of the surgeon in thesurgical procedures in which the blade can be used. Furthermore, bendingthe electrosurgical blade causes the non-stick coating to fracture. Theelectrosurgical blade then begins to rapidly build up charred tissuebecause of exposed etched metal of the blade, and any advantages of thenon-stick coating are lost.

[0007] The non-stick coating of the '807 patent is also specificallydescribed as Teflon (TM). The nature of Teflon (TM) is such that itrequires a high current to be used in cutting and cauterization. This isbecause electrical current must pass through the Teflon (TM) to thetissue. However, this constant passage of current eventually breaks downthe Teflon (TM), leaving small holes or other imperfections in theTeflon (TM) coating. Charred tissue then begins to adhere to the exposedmetal beneath the Teflon (TM) coating. Furthermore, electrical currentwill no longer be uniform across the blade because the current will tendto concentrate at locations where the metal is exposed.

[0008] Another problem in the state of the art electrosurgical bladeswhich utilize Teflon (TM) is that when heated, Teflon disadvantageouslybreaks down and evolves fluorine as a gas. This gas is hazardous to thepatient and the surgical team.

[0009] The information above introduces some of the problems of othernon-stick coatings. However, the problems are associated specificallywith the issues which are involved when using the non-stick coating forelectrosurgical instruments. There are actually numerous otherembodiments of the present invention which are able to take advantage ofthe characteristics of the conductive, non-stick coating which wasoriginally developed to solve problems relating to electrosurgicalinstruments, blood pumps, and other medical devices.

[0010] There are also other problems with state of the art medicaldevices which are made from materials which do not react well or ideallywith body tissue. For example, stents can cause infection andthrombosis, and have lubricity problems. Stents also clot up after someperiod of time, and the body can form scar tissue around the stent. Abio-compatible coating having greater lubricity and which is flexibleenough to expand with the stent when deployed. Stents also tend to stickto the catheter that is used to insert them.

[0011] Catheters also have lubricity problems. They can be difficult toinsert, especially when they are long. They are also hard to extractbecause they can become stuck. Present coatings that are used oncatheters usually do not remain on the catheter, and either have theproperty of bio-compatibility or lubricity, but not both.Nonbio-compatible coatings are usually inflexible and cannot be appliedto flexing plastics such as catheters. Friction during insertion alsoremoves biological and polymeric coatings, and they also wash off whenexposed to flowing fluids, such as blood. The tip of the catheter andthe insertions site also tend to be the site of blood clots. Theseproblems are exacerbated for balloon catheters in which the balloonsticks to the tissue or tears, releasing potentially dangerous gasesinto the body.

[0012] It is also of interest to recognize that most catheters use aradio-opaque metal band to denote the catheter position using X-rayimaging. This band disadvantageously causes crimping of the catheter.The metal band is also known to slip along the length of the catheter,thereby causing false readings of the catheter position in the body. Themetal band providing radio-opacity is also typically large. This canresult in insertion and extraction problems for the catheter. The metalband can also irritate and damage the inner surface of the vesselthrough which the catheter is inserted.

[0013] Guide wires used to install catheters also have problems oflubricity because they provide a frictional surface which resists entryinto and passage through tissue.

[0014] The installation of a shunt is a painful process because of thefriction of the tissue. Furthermore, state of the art shunts are alsolimited in their useful lifespan because they tend to havebio-compatibility problems.

[0015] Needles such as those used in dialysis and for diabetics whichare of large diameter can also cause substantial pain during insertionand cause significant tissue damage.

[0016] Silicone-based medical devices such as inhaler seals,laryngechtomy prostheses, and nasal tampons have several major problems.The solid silicone is sticky and rubbery, and thus these devices arehard to insert and withdraw due to lubricity problems. Some of thesedevices are also subject to infection and thrombosis.

[0017] Trocars are also medical devices which would benefit from abio-compatible coating having a high degree of lubricity. Trocars areused to introduce larger-sized implants and/or surgical tools,especially for minimally invasive surgery. Like needles, they havefriction problems and can cause damage at the site of insertion.

[0018] Soft tissue implants such as breast, penile, and testicularimplants, as well as devices such as pulsatile mechanical blood pumpssuffer from diffusion problems. In the case of breast implants, hugeliability has been incurred from silicone leaking out and causingpotential systemic harm to the body. In the case of blood pumps, theirpumping gases and fluids leak out, with potentially harmful sideeffects, as well as inconvenience caused by additional implantedhardware to replace lost fluids and added cost and inconvenience to thepatient who has to make repeated trips to the hospital. Also, bodyfluids leak in, causing the corrosion of components which eventuallycause device failure. These corrosion problems are also faced byimplantable electrodes, leads, and sensors such as those of pacemakersand defibrillators. Drug containers also have problems of corrosion andchemical reactions, especially with the newer and more potent drugs, aswell as of diffusion of drugs through the container, including therubber stoppers used as the caps of some drug containers.

[0019] It is also mentioned that syringe components such as plungersoften get stuck or caught while pulling in fluid. Often, excessive forceis used while expelling fluids. These situations all combine to reducepatient safety because of increased risk of injury.

[0020] These are also similar problems to contraceptive and OB/Gyndevices which have problems with infection, thrombosis, tissue growthand friction causing irritation and subsequent trauma to surroundingtissue. Likewise, grafts and cuffs such as vascular grafts and varicosevein cuffs have problems with infection and thrombosis. Electrodes,especially those used for esophageal pacing, fetal monitoring, spinalepidural, and for ablation have problems of assuring electricalconductivity to the skin.

[0021] A different problem is raised by electro medical devices whichsuffer from failures caused by inadequate electromagnetic interference(EMI) shielding. Often, this failure relates to the use of plastic andother non-metallic parts in the electrical assembly that cannot beeasily shielded.

[0022] Non-medical devices have other problems as well that could besolved by a coating as described above. For example, magnets havehydrogen embrittlement and subsequent degradation problems. Theseproblems are acute in the new high-strength rare-earth magnets (e.g.Neodymium Iron Boron). This happens because hydrogen diffuses into thematerial and causes failure. Hydrogen embrittlement is also a problem inthe aircraft industry with titanium and other structural materials.

[0023] Another problem that could be solved with a coating as describedabove is the sticking inside of a mold. The molded part sometimes sticksto the mold, destroying the part or the mold. Molds are presently madeprimarily of metal or ceramics, which makes then very expensive to make.

[0024] Disk drives might also benefit from the present invention.Specifically, EMI problems and friction problems could be eliminatedwith a coating like the present invention.

[0025] Another industry which could benefit from such a coating is infootwear. Polyurethane-based soccer shoes suffer from degradation of thepolymer caused by high humidity conditions and subsequent diffusion ofwater vapor across the membranes used in the shoe.

[0026] Integrated circuits suffer from problems of moisture and ioningress which can result in failure of the circuit. Another problem isthe diffusion of gold used in the gold/titanium ohmic contacts.

[0027] Magnetic media could also substantially benefit from such acoating. The degradation over time is often the result of high humidityconditions and physical wear of the material from contact with a read orwrite head.

[0028] Fiber optic conduits could also benefit because they suffer fromthe diffusion of gases and other fluids which causes their opticalproperties to degrade. Superconducting and photo diodes also suffer fromdiffusion barrier problems.

[0029] Fluid valves and solenoids also having sticking problems. Theirmoving parts tend to stick to their static components, resulting inintermittent or terminal component failure.

[0030] All of the problems described above can be alleviated to somedegree, and even altogether eliminated in many cases by a coating whichhas the characteristics of being conductive, having a high degree oflubricity, providing bio-compatibility, flexibility, radio-opacity,diffusion resistance, wear and corrosion resistance, hardness, abilityto be hydrophobic or hydrophilic, adherence to multiple materials,sterilizability, and chemical inertness and stability.

OBJECTS AND SUMMARY OF THE INVENTION

[0031] It is an object of the present invention to provide a conductive,non-stick coating which can be applied to materials which can benefitfrom exhibiting the property of having a surface which functions as iflubricated.

[0032] It is another object to provide a conductive, non-stick coatingwhich has a non-stick coating which will not burn off, wear away orscrape away after repeated exposure to heat, friction and sharp edges.

[0033] It is another object to provide a conductive, non-stick coatingwhich can flex with the material on which it is applied.

[0034] It is another object to provide a conductive, non-stick coatingwhich is a ceramic.

[0035] It is another object to provide a conductive, non-stick coatingwhich uses a conductive ceramic as the non-stick coating.

[0036] It is another object to provide a conductive, non-stick coatingwhich is an amorphous ceramic coating that can flex without breaking ordetaching itself from a substrate to which the coating is applied.

[0037] It is another object to provide a coating which can be applied totemperature-sensitive components which can also provide EMI and radiofrequency interference (RFI) shielding.

[0038] It is another object to increase diffusion resistance for fluidsand gases using the coating which is also flexible enough to preventdiffusion on flexing objects.

[0039] It is another object to provide a coating which can adhere to aplurality of different materials of an assembly so as to provide uniformprotection.

[0040] It is another object to provide a coating which is chemicallyinsert and stable so as to be usable in environments where it isimportant that the coating be non-reactive.

[0041] It is another object to provide a conductive, non-stick coatingwhich uses transition metal nitrides, carbides and oxides as the ceramiccoating.

[0042] It is another object to provide a conductive, non-stick coatingwhich has the ceramic coating applied through sputtering to produce anamorphous ceramic coating.

[0043] It is another object to provide a conductive, non-stick coatingwhich is cost effective to produce, and simple and efficient to apply tovarious substrate surfaces, including metals, plastics, composites,ceramics, semiconductors, magnets, and tissues.

[0044] It is another object to provide a conductive, non-stick coatingwhich is radio-opaque, bio-compatible, diffusion resistant, corrosionresistant, sterilizable, and adherent in nature.

[0045] It is another object to provide a conductive, non-stick coatingat or near room temperature, which permits the coating to be applied tomany heat-sensitive materials and substrates such as plastics,semiconductors, magnets, and tissues.

[0046] In accordance with these and other objects of the presentinvention, the advantages of the invention will become more fullyapparent from the description and claims which follow, or may be learnedby the practice of the invention.

[0047] The present invention provides in a preferred embodiment aceramic coating which is conductive, flexible and provides a surfacewhich functions as if it were lubricated. The manufacturing processproduces a coating of titanium nitride on a surface of a desiredsubstrate material. The coating is amorphous, enabling the substrate tobend if desired.

[0048] One aspect of the invention is the considerably improveddurability of the ceramic coating. Unlike other coatings, the presentinvention does not burn away, flake or scrape off after repeatedexposure to heat and abrasion from sharp edges.

[0049] These and other objects, features, advantages and alternativeaspects of the present invention will become apparent to those skilledin the art from a consideration of the following detailed descriptiontaken in combination with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

[0050]FIG. 1 is a schematic diagram of a sputtering chamber used in thedirect sputtering manufacturing process of the present invention.

[0051]FIG. 2 is a diagram of the components of a pulsatile blood pump,showing where diffusion of gases and liquids occurs which leads tofailure or reduced performance of the pump, and possible healthconsequences to the patient.

[0052]FIG. 3 is a cross-sectional diagram of the presently preferredembodiment for a diffusion barrier in medical devices.

DETAILED DESCRIPTION OF THE INVENTION

[0053] Reference will now be made to the drawings in which the variouselements of the present invention will be given numerical designationsand in which the invention will be discussed so as to enable one skilledin the art to make and use the invention. It is to be understood thatthe following description is only exemplary of the principles of thepresent invention, and should not be viewed as narrowing the claimswhich follow.

[0054] The present invention is comprised of a method of applying theconductive, non-stick coating, at or near room temperature, as well asthe particular materials which can benefit from the coating in theirnormal use. In other words, devices, instruments and various apparatican take advantage of being coated. These devices include those whichcan benefit from a conductive wear resistant coating which can alsoprovide the benefits of being conductive and amorphous (and thusflexible).

[0055] Specifically, the conductive, non-stick coating is a ceramiccoating. In the preferred embodiment, the ceramic coating is composed oftitanium nitride (TiN) which is applied over the substrate by anyappropriate method, such as those to be discussed later.

[0056] Advantageously, the ceramic coating of the present invention canbe applied in relatively thin layers to substrates, typically on theorder of Angstroms.

[0057] Most important to the present invention are the properties of theceramic coating composed of TiN. It should also be mentioned that whilethe preferred embodiment uses TiN as the ceramic coating, there areother ceramics from the family of ceramics known as transition metalnitrides which might be used in the present invention. These ceramiccoating materials include titanium nitride, among others. Thesematerials are classified in terms of properties of hardness, corrosionresistance, color and high spectral reflectance (smoothness). What isimportant to the preferred embodiment of the present invention is thatthe material selected for the ceramic coating 104 have the desirablecharacteristics of TiN. In electrosurgical instruments, it isappreciated that the most important of these characteristics are thatthe coating (a) be conductive, (b) act amorphous after application tothe electrosurgical instrument, and (c) have a high degree of lubricityto thereby flow smoothly through tissue being cut/cauterized. It shouldalso be realized that TiN can be used alone or in combination with othermaterials having desirable characteristics. These other materials mightalso include other conductive (transition metal nitrides) ornon-conductive ceramics.

[0058] Although never applied in an amorphous form by others using aroom-temperature process in any of the applications to be described,Titanium Nitride is a ceramic whose crystalline form is well known forits advantageous properties of hardness, wear resistance, inertness,lubricity, biocompatibility, diffusion resistance, corrosion resistanceand thermal stability in such applications where a low frictioninterface is needed to protect moving parts from wear. While it is theproperties of electrical as well as thermal conductivity jointly withlubricity which make it attractive as a suitable coating for anelectrosurgical blade, it is often the case that only one or two of thecharacteristics of the coating are used by the other embodiments of thepresent invention.

[0059] The preferred process of applying the coating to differentsubstrates is the process of sputtering. However, it is helpful to knowat this stage that advantageously, the TiN can be applied usingsputtering at room or near-room temperatures, significantly simplifyingthe manufacturing process. TiN can also be applied with high dimensionalaccuracy to obtain an even coating thickness along all surfaces. As TiNcan be applied at thicknesses in the Angstrom level, the coated part'sdimensions are not materially affected. Furthermore, TiN exhibits a veryhigh load carrying capacity and toughness. TiN also has excellentadhesion qualities so that it does not spall, even under plasticdeformation of the surface. The high toughness and excellent adhesionproperties are due to a metallurgical bonding between some substratesand the TiN coating. In particular, the TiN coating bonds well withother metals such as steel and stainless steel.

[0060] Most importantly, however, TiN advantageously has high hardnessand low friction coefficients (referred to as lubricity). This propertyof lubricity enables the conductive, non-stick coating to glide throughtissue for extended periods of time between cleaning. But unlike Teflon(TM) coatings, TiN will not burn off or wear away quickly from repeateduse to leave a substrate exposed. The ceramic TiN either has no wear, orwears substantially less than, for example, the Teflon (TM) coating usedin the prior art because Teflon (TM) burns away, and peels off thesubstrate. Consequently, the present invention has a longer usefullifespan.

[0061] Most advantageously, the TiN ceramic coating of the presentinvention also has great flexibility. The coating process allows the TiNto be applied on surfaces which are not normally able to receive such acoating. This includes surface materials such as plastics, magnets,semiconductors, and other heat-sensitive materials including aluminum.The present invention also has a much stronger bond between a base metalsubstrate and its ceramic coating. This bond extends down to themolecular level. More specifically, there is a metallurgical bondingbetween a metallic substrate and the TiN coating. What is created isdefined as an interfacial nanometer layer consisting of both the basemetal substrate and the TiN ceramic coating. This interfacial zone iscreated in the first stage of the coating process when TiN is sputteredonto the base metal substrate. In other words, it is accurate to statethat the TiN ceramic coating can be referred to as an amorphous bond,having no crystalline structure subject to fracturing. The amorphous TiNceramic coating can therefore flex integrally with the base metalsubstrate to which it is attached.

[0062] When examining the potential applications of the non-stickcoating of the present invention, the list is impressive, and rangesfrom simple devices to high-tech equipment. The following list is onlyprovided as an example of applications. Items which can benefit from theceramic coating of the present invention include scissors, knives, drillbits, reamers, saw blades, pliers, end mills, wire cutters, precisioncoining dies, rollers, pins, screws, bore gauges, stamp metal formingtools, extrusion dies, spool lips for spinning reels, counter bores,taps broaches, gear cutters, bearings bushings, gears, splines,actuators, push rods, cams, cam shafts, hobs, punches, valve stems,router bits, engine parts, blanking dies, resistance welding electrodes,scrapers, gouges, countersinks, counterbores, silicon wafers and chips,pump plungers, embroidery needles, VLSI semiconductors, compressorblades/vanes, jewelry, door hardware, writing instruments, eyeglassframes, shafts and seals, marine hardware, plumbing fixtures, slitters,aerospace components, plastic molds, dental instruments and devices,food processing equipment, key duplicators, forming dies, cutting tools,granulator blades, powdered metal dies, seaming rolls, burnishers,engravers, minting devices, razor blades, toy components, umbrellas,optical fibers, integrated circuits, video/audio heads, video/audiotapes, computer floppy disks, packaging, solar cells, kitchen utensils,window panes, golf clubs, bicycle components, reflectors, spark plugs,lamp shades, key chains, piston rings, fluid pumps, super conductingthin films, photo diodes, light emitting diodes, diode lasers,electrodes, electrochemical cells, thermolytic coolers, nuclear fuelpellets, magnetic recording media and heads, fluid valves, solenoids,disk drives, circuits to provide protection from EMI, circuit boards,belts, footwear, UV adhesives, tubing, casters, filters, paper products,actuators, fishing equipment, etc.

[0063] Some of the specific benefits which are provided by the ceramiccoating include biocompatibility, a continuous coating, a smoothcoating, a non-stick coating (reduces friction and eliminates gallingand seizing), it is aesthetically appealing, corrosion resistant, wearresistant, fatigue resistant, sterilizable, generally radio opaque,applicable to flexible surfaces, adheres to a variety of surfaces whichcomprises different materials including composites, is applicable as aroom-temperature process, does not introduce residual stresses, isconductive, is conformal and thin, and can act as a diffusion barrier.

[0064] Other applications include using the coating for integratedcircuits. Specifically, integrated circuits currently use a titaniumgold two-step process for the circuit. The coating should result inhigher yield production, better purity, a higher diffusion barrier,equal or improved conductivity, applied in a one-step process instead oftwo, and should result in less expensive operation.

[0065] Regarding audio/video recording equipment and media, thepotential benefits are increased head life and longevity of the media,improved quality of audio or video reproduction, less wear on the media,and the ability to coat plastics and thereby replace metal heads.

[0066] Regarding kitchen utensils such as pots and pans, the coating canbe applied to aluminum, while Teflon (TM) cannot, it will resistscratching and chipping better, it will result in a pot or pan with alonger life, it is non-stick, and metal spoons, spatulas and other metalutensils can be used without fear of damaging the coating.

[0067] Regarding plastic gears, the potential benefits are improvedwear, less weight, lower costs, maintaining of dimensional accuracy, andlonger life.

[0068] Regarding razor blades, there should be less skin irritation,lower costs of producing blades, improved quality, and a large marketingadvantage.

[0069] Regarding spark plugs, the coating should provide longer life,reduced fouling and improved performance, particularly in the two cycleoil-mix variety.

[0070] In summary, the TiN ceramic coating of the present inventionprovides many unique advantages over the prior art. The TiN ceramiccoating does not significantly wear or burn off, thereby providingimproved reliability and durability, and not evolving by-product gases.Advantageously, the TiN ceramic coating can also be repeatedly cleanedso that the device which is coated can be reused many times.Furthermore, many different sterilization techniques can be used withoutdamaging the TiN coating.

[0071] While the invention teaches that the substrate can be stainlesssteel, other materials can also be used. These other materials mightalso be conductive metals such as titanium, but can also includenon-conductive materials such as plastics.

[0072] A final advantage in these non-medical applications describedabove concerns the manufacturing process for applying the ceramiccoating. In a preferred embodiment, the TiN ceramic coating is appliedto a stainless steel blade using a room temperature direct sputteringprocess. Sputtering is a room or relatively low temperature process bywhich a controlled thin film of Titanium Nitride is uniformly depositedon the stainless steel blade or any other substrate.

[0073] The sputtering process itself is relatively simple, and hasnumerous advantages for the present invention. For example, thesputtering process does not change the characteristics of the base metalsubstrate or the TiN ceramic coating. The other advantages becomeobvious with an examination of the sputtering process.

[0074] There are two forms of sputtering which are described herein. Thefirst form of sputtering is known as direct sputtering. This means thatthe sputtering is done directly from a TiN source. TiN sources areavailable commercially, and pure TiN can be coated onto a base metalsubstrate using radio frequency sources in a non-reactive atmosphere.

[0075] Another method of applying TiN to a base metal substrate isthrough the process of reactive sputtering. In this process, thereactive atmosphere must be composed of nitrogen. The titanium reactswith the nitrogen atmosphere to form titanium nitride. The TiN thencoats the surface of the stainless steel.

[0076] The process of both direct and reactive sputtering involves muchof the same equipment as shown in FIG. 1. The sputtering takes place ina stainless steel chamber 10. In this preferred embodiment, thestainless steel chamber 10 has dimensions of approximately 18 inches indiameter and 12 inches in height. The actual sputtering function isaccomplished by sputtering guns 12 which are generally located at thetop of the stainless steel chamber 10. The sputtering guns 12 arecapable of movement in both the horizontal and vertical directions asdesired.

[0077] The sputtering system described above is accomplished usingstandard equipment readily available for manufacturing. An example ofthe direct sputtering process is as follows. The stainless steel chamber10 is evacuated of ambient air through evacuation port 14. An inert gassuch as argon is then fed into the stainless steel chamber 10 through agas port 16. The argon gas is ionized using the cathode 18 and the anode20 to generate an ion flux 22 which strikes the Titanium Nitride 24. Theimpact of the ion flux 22 will eject TiN sputtered flux 26 which travelsand adheres to the base substrate 30. It is important to note that thereare other sputtering processes well known to those skilled in the artwhich are also appropriate for applying the TiN ceramic coating 26.

[0078] While sputtering times may vary, experimentally it has beendetermined that the sputtering time is generally 1 to 1.5 hours togenerate a TiN ceramic coating 26 on the base metal substrate 30 whichis approximately 0.5 microns thick. Generally it has been found that thesputtering process applies the TiN ceramic coating 26 according to alinear function, so the application time is easily adjusted accordinglyto obtain the desired thickness. The 0.5 micrometer thick TiN coatingthus corresponds to a TiN deposition rate of approximately 1 angstromthickness being added every second.

[0079] The process above has described the application process forapplying the ceramic coating to a metallic substrate. In general, it isimportant to understand that sputtering is a momentum transfer process.It is a process wherein constituent atoms of the material are ejectedfrom surface of a target because of momentum exchange associated withbombardment by energetic particles. The bombarding species are generallyions of heavy inert gas, usually argon. Sputtering may be used for bothsurface etching and/or coating. The flux of sputtered atoms that maycollide repeatedly with the working gas atoms before reaching thesubstrate where they condense to form a coating of the target material.

[0080] A key difference between coating on metals and coating onplastics is that plasma is used to modify and/or pretreat the surface ofthe plastic to a greater extent on plastics than on metals. For coatingcertain plastics such as silicone, a plasma treatment can be given in aseparate chamber or by using the same sputtering machine used forcoating at lower energy levels at which plasma forms but no or minimalsputtering occurs. This pre-treatment helps the coating adhere better tothe plastic substrate. For the pre-treatment of plastics to be coated,the plastic surface is in contact with the plasma, and plasma ionbombardment on the surface modifies the plastic surface by plasmaetching which is more conducive to receiving the target atoms. Thispromotes a dense, fine-grained amorphous structure on the surfacedepending on the process conditions such as pressure and power. Thebombardment effects will give the target atoms enough energy to get intothe surface layers of the plastic, thereby giving excellent bonding ofthe coating with the substrate. The flux of sputtered material leavingthe target will be identical in composition to the target.

[0081] The quality of the coating depends on the sputter emissiondirections, the gas phase transport, and the substrate-stickingcoefficient of the constituents. Because the coating target materialtransfers to vapor phase by a mechanical process (momentum transfer)rather than by a chemical or thermal process, the heating of thesubstrate can be controlled by carefully adjusting the conditions(keeping sputtering energy levels and thus temperatures low). Thisadjustment makes it possible to coat plastic surfaces at room or nearroom temperature without damaging the substrate.

[0082] While the presently preferred method of application of theceramic to the substrate is through sputtering, it should be apparentthat there are other methods. These include such methods as CVD andplasma deposition. Therefore, the application method of sputteringshould not be considered limiting in the present invention.

[0083] It should be mentioned that TiN also differs from other state ofthe art coatings for base metals in that it does not evolve dangerousgases. When heated, TiN does not evolve any gases.

[0084] While the presently preferred embodiment of the inventionemphasize the amorphous coating of a ceramic on the base metalsubstrate, it should also be realized that crystalline coatings can alsobe used.

[0085] The materials to which the ceramic coating of the presentinvention is applied above are generally considered those which arefound specifically in non-medical applications. However, the obviousbenefits of the present invention to the medical industry should beexamined carefully because of the substantial benefits that can result.

[0086] From a short list of the medical devices, implants andinstruments which can be coated with the ceramic coating of the presentinvention, the advantages of the present invention become more obvious.First, mechanical devices which can benefit from the present inventioninclude blood pumps such as Ventricular Assist Devices, ArtificialHearts, Intra-Aortic Balloon Pumps and Impellers. The coating is appliedto most plastic, metallic and ceramic components including magnets whichcan be coated at the room or near room temperature process to therebynot affect the magnetic properties. Furthermore, the coating providessuch advantageous features as bio-compatibility including non-toxicity,even when the underlying material might not be bio-compatible. Thecoating can also function as corrosion resistance, and even as adiffusion barrier.

[0087] Not only can the coating of the present invention be applied tothe blood-contacting surfaces, but also to the exterior of implanteddevice. Such devices include balloons such as epitaxis, catheter,occluder, intra-aortic balloons and angioplasty balloons. The coatingcan also be disposed on diaphragms, volume displacement chambers, andassociated fluid paths in plastic tubes.

[0088] When addressing motors, the coating can also be used on bearingsand bearing components. These components include balls, pivots, andinner and outer races used in actuators for medical devices. The resultis a reduction in wear and thus increased lifespan of the medicaldevices.

[0089] Other medical devices that can benefit are catheters, especiallythose used in long-term indwelling procedures, cardiotomy andcerebrovascular, and those needing a safer and more reliableradio-opaque covering or marker. Soft-tissue implants includeintravaginal and colostomy pouches, breast implants, penile andtesticular implants.

[0090] Valves of the type used in hearts can also be improved by thecoating disposed on disks and struts. Existing stents made from metal,ceramic and plastic and used for an annulplasty ring can be coated toprovide the desired flexible and bio-compatible outer covering.

[0091] Shunts such as a dialysis shunt, an A-V shunt, a central nervoussystem shunt, an endolymphatic shunt tube, a peritoneal shunt and ahydrocephalys shunt can also be coated.

[0092] Silicone-based medical devices including inhaler seals, valvesfor laryngechtomy prostheses, nasal tampons, and tubes can also becoated.

[0093] The present invention can also serve to coat a plastic sheathcovering current-carrying loads, as well as the leads themselves,connectors, feedthroughs for any implanted, electrically powered devicesuch as a pacemaker, defibrillator, cardioverter, bipotential electrodesand leads, neural stimulators such as a cerebellar, brain, cranial,nerve and spinal cord device. The implanted devices can also be opticalor cochlear in nature.

[0094] Other devices that can benefit include arterial filters, vasculargrafts, varicose vein cuffs, as well as intracardiac, pledget,pericardial and epicardial patches. Contraceptive and Ob/Gyn devicesinclude a plug prostheses, tubal occlusion devices (band, clip, insertand valve), urethal devices such as a stent, dilator and a catheter,IUDs and diaphragm. Other devices include an angiographic and otherguide wire.

[0095] Sensors and transducers which are of the implantable variety aswell as the non-implantable short-term variety can be coated. Theseinclude those used in measuring blood flow, blood pressure, vascularaccess devices, those which can be protected with a conductive layer ofthe coating, a catheter tip pressure transducer, and an invasive glucosesensor. The coating itself can be used as sensing material which detectschanges in its property such as conductivity as a function of the thingbeing measured.

[0096] Occluders include those used in patent ductus arteriosus. Atracheotomy tube can also be coated.

[0097] Finally, hermetically sealed cans and other enclosures having aplastic-based substrate can be coated, including those used to encaseelectronics of any type, for actuators, sensors and fluids.

[0098] Surgical instruments and devices can also be coated. Such devicesinclude catheters of all types, needles, trocars, feeding/breathingtubes, transfusion tubes, clips, surgical staples, electrosurgicalinstruments, pumps, as well as knives, scalpels, scissors, clamps,coagulators, dilators, retractors, examination gloves, non-absorbablesutures and ligatures, microtomes, surgical meshes, tonsil dissectors,and vascular clamps, stereotaxis instruments and accessories, and heatexchangers.

[0099] There are also various orthopedic devices that can be coated,such as synthetic ligaments and tendons, fallopian tube replacements,ear prostheses, Stiennman Pins, bone plates and skull plates.

[0100] Measuring and analytical devices include blood measuring andevaluating devices, blood collection systems, containers for blood andother sensitive fluids, linings, tubes and blood-contacting surfaces oflaboratory instruments, and coatings for leads used in such things as anEEG, ECG, etc.

[0101] Other devices that can be coated are syringes, plungers, intraocular lenses, drug containers and packaging.

[0102] It should ne be surprising that the preceding pages do notrepresent an exhaustive list of all of the possible medical devices,instruments and applications of the present invention, but it serves tosuggest many of the applications.

[0103] One particularly important medical application of the presentinvention is in diffusion barriers. Many implantable devices such as ablood pump, as well as soft-tissue implants (breast, penile andtesticular) have diffusion barriers containing fluids. The diffusionbarriers are supposed to prevent the passage of working fluids (such asa lubricating oil) from within the medical device to the body. Likewise,body fluids (blood) are not supposed to enter into the medical device.However, it is the case that diffusion barriers are soft membranes whichare disadvantageously permeable to gases and fluids. The presentinvention functions as a diffusion barrier to prevent or at least reducethe passage of gases and fluids through the permeable membranes.

[0104] To understand the nature of the problem, it is helpful to look ata diagram of a pulsatile blood pump. FIG. 2 is a blood pump 40. Theblood pump 40 has a pumping chamber 42 in which is disposed apolyurethane membrane 44 which functions as a diaphragm. On one side ofthe membrane 44 is blood 46. On the other side of the membrane 44 is aworking fluid 48 of the blood pump 40. The pumping chamber 42 is coupledvia an energy converter 50 to a volume displacement chamber 52. Withinthe volume displacement chamber 52 is the working fluid 48 of the bloodpump 40.

[0105] The arrows 54 indicate that diffusion occurs through the membrane44 between the blood 46 and the working fluid 48 in the pumping chamber42, and between the working fluid 48 and tissues 56 which surround thevolume displacement chamber 52. It should be remembered that the workingfluid 48 of the blood pump 40 is typically some of type of lubricatingoil such as silicone oil. Obviously, it is desirable to prevent blood 46and working fluid 48 from passing through the flexible membrane 44.

[0106] Presently, existing pulsatile pumps accept diffusion of blood andworking fluids, and simply try to treat the symptoms of the problem. Inother words, the pulsatile pumps are often provided with a priming portfor receiving gas or working fluids.

[0107] Allowing diffusion is detrimental to the pulsatile pumps forseveral reasons. First, providing a priming port enables contaminants toenter into the device, thus increasing the chances of infection. Second,the passage of blood into the pumping mechanism increases speed ofcorrosion of internal components, and thus increases the chances offailure of the device.

[0108] There remain unanswered questions regarding the long-term healtheffects of silicone. It is reported that connective tissue diseases andbreast cancer are one result. However, it is obviously prudent to reducethe introduction of silicone oils into the blood stream.

[0109] It has been determined experimentally that some pulsatile bloodpump devices will lose between 10 and 15 cc's of silicone oil into thebody per year. The loss of this volume of working fluid is alsodetrimental to the operation of the device because it reduces the strokevolume, for example, by 15% to 25%. Such a loss in stroke volume islikely to be an unacceptably high loss. However, electrohydraulic pumpsare not the only ones whose performance suffers from diffusion.Pusher-plate devices are also susceptible to failure.

[0110] Referring to the volume displacement chambers, the membranes usedin these chambers also allow body fluids into the device. These bodyfluids contain ions and moisture which cause corrosion and wear of theblood pump's energy converter, thus leading to eventual failure of thepump due to short-circuiting or corrosion.

[0111] Previous attempts to reduce permeability of the membrane havefailed to stop diffusion. For example, multiple membrane layers ordifferent membrane materials have been tried. Unfortunately, none ofthese attempts have succeeded.

[0112] The present invention advantageously reduces diffusion of workingfluids and blood through the membrane by coating the membrane with aflexible, bio-compatible, corrosion resistant ceramic coating.

[0113]FIG. 3 is a cross-sectional profile view of the presentlypreferred embodiment of a membrane 60 to be used in a pumping mechanism.In the presently preferred embodiment, a layer of the ceramic coating 62is disposed between two layers 64 and 66 of the membranes. In thisembodiment, polyurethane is used for the membranes 64 and 66.

[0114] The thickness of the ceramic coating 62 has experimentally beendetermined to be within the range of approximately 5000 to 10,000angstroms. The ceramic coating 62 is deposited on one of thepolyurethane membranes 64 or 66 after vacuum forming or solutioncasting. During sputtering, the polyurethane surface is energized by theargon plasma. Accordingly, the ions of the ceramic coating material willactively bond with the surface, thus creating a diffusion layer which isamorphous.

[0115] The second layer of polyurethane will form an active surfacewhile heated during vacuum forming. During solution casting, the polymerwill be in a liquid phase, enabling the polyurethane to enter surfacemicro-irregularities of the ceramic coating. This bonding will preventsurface delamination.

[0116] Because amorphous Titanium Nitride is insert, fatigue resistance,bio-compatible, corrosion resistant and lightweight. Furthermore, TiN ishydrophobic, and thus prevents the diffusion of any liquids through itssurface. It is possible to also make the surface hydrophilic byappropriate surface plasma treatments. Diffusion occurs predominantlyalong grain boundaries. Since the amorphous nature of the TiN coatingdoes not have any grain boundaries, diffusion through the TiN ceramiclayer 62 is greatly reduced.

[0117] When examining other materials to use as a diffusion barriercoating between the polyurethane layers, it is observed that gold canalso be sputtered. However, gold is likely to fail due to its lowfatigue resistance under continuous flexing and stretching conditions ofthe membrane in a blood pump. Furthermore, gold is relatively expensivecompared to TiN. Silver and copper are corrosive and hence cannot beused in this medical application.

[0118] However, it is possible that other ceramics of the family of TiNcan be used as the diffusion barrier. These ceramics include AluminumOxide, Titanium Carbide, Silicon Carbide, Silicon Nitride, Boron Nitrideand Zirconia. The advantages of these ceramics is that like TiN, theyprovide an amorphous coating through sputtering, they also inhibitpermeability of gases and fluids, they can be deposited at room ornear-room temperature, they can be applied to multiple materials tothereby provide a same coating on different parts and materials of thepump, and they are all bio-compatible.

[0119] It is to be understood that the above-described embodiments areonly illustrative of the application of the principles of the presentinvention. Numerous modifications and alternative arrangements may bedevised by those skilled in the art without departing from the spiritand scope of the present invention.

What is claimed is:
 1. A method for providing a wear-resistant ceramiccoating on a substrate material which is used in an abrasiveenvironment, such that the substrate material is not deformed during aprocess of applying the wear-resistant ceramic coating, said methodcomprising the steps of: (1) selecting the ceramic coating from thegroup of ceramics consisting of transition metal nitrides which are bothamorphous and conductive; and (2) using a generally room temperatureapplication process to apply the wear-resistant ceramic coating to thesubstrate material such that the substrate material is not deformed. 2.The method as defined in claim 1 wherein the method further comprisesthe step of applying a wear-resistant ceramic coating which isamorphous.
 3. The method as defined in claim 1 wherein the methodfurther comprises the step of applying at least two ceramic materialswhich are transition metal nitrides.
 4. The method as defined in claim 1wherein the method further comprises the step of applying (i) at leastone ceramic to the substrate material which is a transition metalnitride, and (ii) at least one material which is not a transition metalnitride.
 5. The method as defined in claim 1 wherein the method furthercomprises the step of applying a wear-resistant ceramic coating which isconductive to thereby facilitate propagation of electrical energy alongthe substrate material.
 6. The method as defined in claim 1 wherein themethod further comprises the step of applying a wear-resistant ceramiccoating which is not worn away by application of RF energy thereto, byabrasion or by repeated sterilization thereof.
 7. The method as definedin claim 1 wherein the method further comprises the step of deformingthe substrate material from a resting state, and wherein thewear-resistant ceramic coating is flexible so as to be deformed with thesubstrate material without damage to the wear-resistant ceramic coating.8. The method as defined in claim 1 wherein the method further comprisesthe step of depositing the wear-resistant ceramic coating on thesubstrate material using a room or near room temperature sputteringprocess.
 9. The method as defined in claim 1 wherein the method furthercomprises the step of applying the wear-resistant ceramic coating as acontinuous coating over the substrate material.
 10. The method asdefined in claim 1 wherein the method further comprises the step ofapplying the wear-resistant ceramic coating as a corrosion resistantcoating over the substrate material.
 11. The method as defined in claim1 wherein the method further comprises the step of applying thewear-resistant ceramic coating as a fatigue resistant coating over thesubstrate material.
 12. The method as defined in claim 1 wherein themethod further comprises the step of applying the wear-resistant ceramiccoating as a sterilizable and biocompatible coating over the substratematerial.
 13. The method as defined in claim 1 wherein the methodfurther comprises the step of applying the wear-resistant ceramiccoating as a radio frequency opaque coating over the substrate material.14. The method as defined in claim 1 wherein the method furthercomprises the step of applying the wear-resistant ceramic coating as aconformal coating over the substrate material.
 15. The method as definedin claim 1 wherein the method further comprises the step of applying thewear-resistant ceramic coating as a generally smooth and non-stickcoating over the substrate material.
 16. The method as defined in claim1 wherein the method further comprises the step of depositing thewear-resistant ceramic coating using room or near room temperaturesputtering.
 17. The method of manufacturing as defined in claim 16wherein the method comprises the further step of sputtering titaniumnitride onto the substrate material.
 18. The method as defined in claim1 wherein the method further comprises the step of selecting thesubstrate material for the substrate materials consisting of plastics,glass, ceramics, metals, composites, magnetic materials andsemiconductors.
 19. The method as defined in claim 1 wherein the methodfurther comprises the step of applying the wear-resistant ceramiccoating as shielding against electro magnetic interference.
 20. Themethod as defined in claim 1 wherein the method further comprises thestep of applying the wear-resistant ceramic coating as shielding againstradio frequency interference.
 21. The method as defined in claim 1wherein the method further comprises the step of applying thewear-resistant ceramic coating as a chemically inert, non-reactive andstable coating.
 22. The method as defined in claim 1 wherein the methodfurther comprises the step of applying the wear-resistant ceramiccoating as a diffusion barrier, wherein the diffusion barrier reduces apassing of fluids and gases therethrough.
 23. The method as defined inclaim 22 wherein the method further comprises the step of selecting asthe diffusion barrier a bio-compatible coating which is amorphous, tothereby enable the diffusion barrier to flex without damaging thebio-compatible coating.
 24. The method as defined in claim 22 whereinthe method further comprises the step of terminating any exchange ofgases or fluids through the diffusion barrier, thereby eliminating anyexchange of gases or fluids.
 25. The method as defined in claim 22wherein the method further comprises the step of forming the diffusionbarrier on an otherwise permeable membrane which otherwise enables anexchange of fluids and gases therethrough.
 26. The method as defined inclaim 1 wherein the method further comprises the step of applying anadherent ceramic coating which readily couples to the substratematerial.
 27. The method as defined in claim 1 wherein the methodfurther comprises the steps of: (1) providing a plurality of differentsubstrate materials in a single assembly; and (2) applying the ceramiccoating to the plurality of different substrate materials of the singleassembly such that the ceramic coating is applied to all surfacesthereof.
 28. The method as defined in claim 18 wherein the magneticmaterials are selected from the group of magnetic materials consistingof magnetic tape, ceramic magnets, rare-earth magnets, and metallicmagnets, wherein the magnetic materials are thereby protected frommoisture which can damage the magnetic materials.
 29. The method asdefined in claim 1 wherein the method further comprises the step ofapplying the wear-resistant ceramic coating to components of a storageunit for a computer, wherein the storage unit includes a magnetic mediawhich is caused to rotate, said wear-resistant ceramic coating reducingfriction of movable components thereof.
 30. The method as defined inclaim 29 wherein the method further comprises the step of at leastpartially coating the storage unit with the ceramic coating to therebyprovide protection from EMI and RFI.
 31. A method for providing awear-resistant ceramic coating on a semiconductor material which is usedas part of an integrated circuit, such that the semiconductor materialachieves increased conductivity and reduces diffusion of componentsthereof, said method comprising the steps of: (1) selecting the ceramiccoating from the group of ceramics consisting of transition metalnitrides which are both amorphous and conductive; and (2) using agenerally room temperature application process to apply the ceramiccoating to the semiconductor material such that the semiconductormaterial is more conductive and so that there is reduced diffusionbetween elements of the semiconductor material.
 32. A method forproviding a wear-resistant ceramic coating on a magnetic material whichcan be damaged by application of thermal energy, such that the magneticmaterial retains its magnetic properties during a process of applyingthe wear-resistant ceramic coating, said method comprising the steps of:(1) selecting the ceramic coating from the group of ceramics consistingof transition metal nitrides which are both amorphous and conductive;and (2) using a generally room temperature application process to applythe wear-resistant ceramic coating to the magnetic material such thatthe magnetic material is not deformed.
 33. A method for providing awear-resistant ceramic coating on a heat-sensitive material which isused in an abrasive environment, such that the heat-sensitive materialis not deformed during a process of applying the wear-resistant ceramiccoating, said method comprising the steps of: (1) selecting the ceramiccoating from the group of ceramics consisting of transition metalnitrides which are both amorphous and conductive; and (2) using agenerally room temperature application process to apply thewear-resistant ceramic coating to the heat-sensitive material such thatthe heat-sensitive material is not deformed.
 33. A method for providinga wear-resistant ceramic coating on a material which is used in anenvironment which is detrimental to the material, such that the materialis covered with a continuous, smooth and fatigue resistant ceramiccoating after an application process thereof, said method comprising thesteps of: (1) selecting the ceramic coating from the group of ceramicsconsisting of transition metal nitrides which are both amorphous andconductive; and (2) using a generally room temperature applicationprocess to apply the wear-resistant ceramic coating to the material suchthat to thereby enhance properties of wear resistance, lubricity andstrength.
 34. The method as defined in claim 33 wherein the material isselected from the group of products including kitchen utensils, gears,spark plugs, molds, plumbing fixtures, eyeglass frames, cuttinginstruments, moisture barriers, sporting goods, writing instruments,drilling instruments, fasteners, bearings, bushings, electrical devices,semiconductors, jewelry, engine components, toys, packaging, opticalinstruments, fuel cells, and recording media.
 35. A method for providinga wear-resistant ceramic coating on a ceramic material which can bedamaged by application of thermal energy, such that the ceramic materialretains its properties during a process of applying the wear-resistantceramic coating, said method comprising the steps of: (1) selecting theceramic coating from the group of ceramics consisting of transitionmetal nitrides which are both amorphous and conductive; and (2) using agenerally room temperature application process to apply thewear-resistant ceramic coating to the ceramic material such that theceramic material is not deformed.
 36. An audio system including aplayback head for use in reading data from an analog media which isdisposed in contact with the audio playback head and moved thereoverduring playback, said audio playback head comprising: the audio playbackhead which is capable of generating electrical signals in response tothe analog media being moved thereover, said electrical signals beingindicative of acoustical signals recorded on the analog media; awear-resistant ceramic coating disposed on the audio playback head tothereby increase resistance to wear thereof and to thereby extend ausable life of the audio playback head.
 37. The audio playback head asdefined in claim 36 wherein the audio playback head is capable ofrecording analog signals to the analog medium.
 38. The audio playbackhead as defined in claim 36 wherein the audio playback head is capableof playback of video data stored as analog data on the analog medium.39. A container for use in cooking wherein the cooking container isexposed to heat to thereby heat the cooking container and food contentstherein, said cooking container comprising: an outer surface; an innersurface on which the food contents are disposed to thereby enabletransfer of heat from the inner surface to the food contents; and awear-resistant and non-stick ceramic coating disposed on the innersurface to thereby enable metal utensils to be used in movement of thefood contents without damaging the inner surface of the cookingcontainer.
 40. A plastic gear for use in applications where weight isrelevant, said plastic gear comprising: a generally circular disk havinga plurality of splines on an outer edge thereof, wherein the pluralityof splines are designed so as to mesh with splines of another device tothereby transmit or receive force thereby; a wear-resistant ceramiccoating disposed on the plurality of splines to thereby provide enhancewear-resistance, maintain dimensional accuracy, and improve a usefullifespan thereof.
 41. A razor blade for use in shaving, wherein saidblade is relatively longer lasting because it is coated with awear-resistant ceramic coating having improved lubricity, said razorblade comprising: a substrate having at least one cutting edge, whereinthe substrate is designed for being pulled across skin to thereby removehair from the skin; and a continuous ceramic coating disposed on thesubstrate to thereby cover the at least one cutting edge with anamorphous coating which resists wear caused by cutting hair, and whichcan flex with the substrate without damaging the continuity of thecontinuous ceramic coating.
 42. A spark plug for use in generating anelectrical spark for igniting a mixture of fuel and air in aninternal-combustion engine, said spark plug comprising: a firstelectrode for carrying an electrical charge from a power source; asecond electrode for receiving the electrical charge from the powersource; an electrically conductive, non-stick ceramic coating disposedon the first and the second electrodes to thereby increase conductivityand provide a surface which is resistant to a build-up of materialswhich can interfere with generation of the electrical spark.
 43. Amethod for providing a wear-resistant ceramic coating on a ceramicmaterial which can be damaged by application of thermal energy, suchthat the ceramic material retains its properties during a process ofapplying the wear-resistant ceramic coating, said method comprising thesteps of: (1) selecting the ceramic coating from the group of ceramicsconsisting of transition metal nitrides which are both amorphous andconductive; and (2) using a generally room temperature applicationprocess to apply the wear-resistant ceramic coating to the ceramicmaterial such that the ceramic material is not deformed and altered inits physical properties.
 44. A method for providing a bio-compatiblecoating on a temperature-sensitive material which is used in a medicaldevice, such that the temperature sensitive material is not damagedduring a process of applying the bio-compatible coating, said methodcomprising the steps of: (1) selecting the bio-compatible coating fromthe group of ceramics consisting of transition metal nitrides which areboth amorphous and conductive; (2) using a generally room temperatureapplication process to apply the bio-compatible ceramic coating to thetemperature-sensitive material such that the temperature-sensitivematerial is not damaged by thermal energy from the application process;and (3) disposing the temperature-sensitive material with itsbio-compatible coating in the medical device, to thereby enable themedical device to be utilized in a medical environment.
 45. The methodas defined in claim 44 wherein the method further comprises the step ofselecting the temperature-sensitive material from the group oftemperature-sensitive materials including plastic, glass, and magneticmaterials.
 46. The method as defined in claim 44 wherein the methodfurther comprises the step of selecting the bio-compatible coating fromthe group of ceramics which provide corrosion resistance.
 47. The methodas defined in claim 46 wherein the method further comprises the step ofselecting the bio-compatible coating from the group of ceramics whichprovide a surface texture of lubricity.
 48. The method as defined inclaim 47 wherein the temperature-sensitive material is a plasticintroducer catheter which is able to be more easily inserted because ofthe plastic introducer's lubricity.
 49. The method as defined in claim44 wherein the method further comprises the step of applying thebio-compatible coating to a plurality of permanent magnets which areused in an implantable medical device requiring an electric motor,magnetic bearing, sensor and other electromagnetic devices foroperation.
 50. A method for utilizing nonbio-compatible materials in animplantable medical device, wherein the implantable medical device ismade safe for implantation, said method comprising the steps of: (1)selecting a bio-compatible coating from the group of ceramics consistingof transition metal nitrides which are both amorphous and conductive;(2) using a generally room temperature application process to apply thebio-compatible ceramic coating to the nonbio-compatible materials suchthat the nonbio-compatible materials are covered completely by thebio-compatible ceramic coating; and (3) implanting the nonbio-compatiblematerial which is coated with the bio-compatible coating.
 51. The methodas defined in claim 50 wherein the method further comprises the step ofusing less expensive nonbio-compatible materials to thereby reduce costsof the implantable devices.
 52. The method as defined in claim 51wherein the method further comprises the step of utilizingtemperature-sensitive materials for the nonbio-compatible materials,wherein the temperature-sensitive materials are selected from the groupof temperature-sensitive materials consisting of plastics, glass, andmagnetic materials.
 53. The method as defined in claim 52 wherein themethod further comprises the step of selecting the implantable devicesfrom the group of implantable devices consisting of stents, ventricularassist devices, pumps, impellers, balloons, diaphragms, volumedisplacement chambers, plastic tubes providing fluid paths, bearings,bearing components, catheters, occluders, soft-tissue implants, valves,shunts, pacemakers, defibrillators, cardioverters, electrodes, neuralstimulators, filters, grafts, patches, contraceptive devices, sensors,transducers, needles, medical tubes, clips, surgical staples, prosthesesand electrosurgical blades.
 54. A method for creating a more effectivediffusion barrier for a medical device, wherein the diffusion barrier isdisposed on a permeable membrane through which fluids and gases are ableto pass, said method comprising the steps of: (1) selecting abio-compatible coating for the diffusion barrier; and (2) applying thebio-compatible coating to the diffusion barrier using a generally roomtemperature application process to thereby avoid damaging the permeablemembrane, wherein the bio-compatible coating reduces penetration of thefluids and gases therethrough.
 55. The method as defined in claim 54wherein the method further comprises the step of selecting abio-compatible coating which is amorphous to thereby enable thediffusion barrier to flex without damaging the bio-compatible coating.56. The method as defined in claim 55 wherein the method furthercomprises the step of reducing an exchange of working fluids and bodyfluids.
 57. The method as defined in claim 56 wherein the method furthercomprises the step of reducing the exchange of working fluids which areselected from the group of working fluids including silicone oil, otherlubricants and air.
 58. A diffusion barrier for use in an implantablemedical device which is exposed to body fluids, wherein the diffusionbarrier reduces passage of working fluids between the implantablemedical device and the body fluids, said diffusion barrier comprising: afirst membrane which is disposed between the body fluids and the workingfluids; an amorphous, bio-compatible, ceramic coating which is appliedon a first side through a room or near room temperature process to afirst side of the first membrane, wherein the amorphous, bio-compatible,ceramic coating is integrally bonded to the first membrane; and a secondmembrane which is bonded to a second side of the amorphous,bio-compatible, ceramic coating.
 59. The diffusion barrier as defined inclaim 58 wherein the first membrane and the second membrane arecomprised of a polymer.
 60. The diffusion barrier as defined in claim 59wherein the polymer is comprised of polyurethane.
 61. The diffusionbarrier as defined in claim 58 wherein the amorphous, bio-compatible,ceramic coating is selected from the group of ceramics consisting oftransition metal nitrides which are both amorphous and conductive, andwhich are also fatigue-resistant, corrosion-resistant, andabrasion-resistant.
 62. The diffusion barrier as defined in claim 58wherein the working fluids are also comprised of working gases.
 63. Amethod for preventing diffusion of fluids between an implantable medicaldevice which is exposed to body fluids, and working fluids of theimplantable medical device, said method comprising the steps of: (1)providing a first membrane which is disposed between the body fluids andthe working fluids; (2) disposing an amorphous, bio-compatible, ceramiccoating on a first side thereof to a first side of the first membranethrough a room or near room temperature process, wherein the amorphous,bio-compatible, ceramic coating is integrally bonded to the firstmembrane; and (3) disposing a second membrane to a second side of theamorphous, bio-compatible, ceramic coating, wherein said ceramic coatingreduces diffusion of the body fluids and the working fluids through thefirst membrane and the second membrane.
 64. A method for preventingdiffusion of fluids between an implantable medical device which isexposed to body fluids, and working fluids of the implantable medicaldevice, said method comprising the steps of: (1) providing a firstmembrane which is disposed between the body fluids and the workingfluids; and (2) disposing an amorphous, bio-compatible, ceramic coatingon a first side thereof to a first side of the first membrane through aroom or near room temperature process, wherein the amorphous,bio-compatible, ceramic coating is integrally bonded to the firstmembrane, wherein said ceramic coating reduces diffusion of the bodyfluids and the working fluids through the first membrane.